There is evidence of some limited prehistoric occupation around the Watford area, with a few Celtic and Roman finds, though there is no evidence of a settlement until much later.[4] Watford stands where the River Colne could be crossed on an ancient trackway from the southeast to the northwest. Watford's High Street follows the line of part of this route.[5][6] The town was located on the first dry ground above the marshy edges of the River Colne. The name Watford may have arisen from the Old English for "waet" (full of water – the area was marshy), or "wath" (hunting), and ford.[4]St Albans Abbey claimed rights to the manor of Cashio (then called "Albanestou"), which included Watford, dating from a grant by King Offa in AD 793.[7]

The name Watford is first mentioned in an Anglo-Saxon charter of 1007, where "Watforda" is one of the places marking the boundary of "Oxanhaege". It is not mentioned in the Domesday Book of 1086, when this area was part of St Albans' Abbey's manor of cashio. In the 12th century the Abbey was granted a charter allowing it to hold a market here and the building of St Mary's Church began. The settlement's location helped it to grow, since as well as trade along this north-south through route it possessed good communications into the vale of St Albans to the east and into the Chiltern Hills along the valley of the River Chess to the west. The town grew modestly, assisted by travellers passing through to Berkhamsted Castle and the royal palace at Kings Langley. A big house was built at Cassiobury in the 16th century. This was partly rebuilt in the 17th century and another substantial house was built nearby at The Grove. The houses were expanded and developed throughout the following centuries. Cassiobury became the family seat of the Earls of Essex, and The Grove the seat of the Earls of Clarendon.[4][8]

In 1762, Sparrows Herne Turnpike Road was established across the Chilterns. The toll road followed approximately that of the original A41 road. The location of a toll house can be seen at the bottom of Chalk Hill on the Watford side of Bushey Arches close to the Wickes hardware store; set in an old flint stone wall is a Sparrows Herne Trust plaque.[9]

In 1778, Daniel Defoe described Watford as a "Genteel market town, very long, having but one street".[10]

Watford remained an agricultural community with some cottage industry for many centuries. The Industrial Revolution brought the Grand Junction Canal (now Grand Union Canal) from 1798 and the London and Birmingham Railway from 1837, both located here for the same reasons the road had followed centuries before, seeking an easy gradient over the Chiltern Hills. The land-owning interests permitted the canal to follow closely by the river Gade, but the prospect of smoke-emitting steam trains drove them to ensure the railway gave a wide berth to the Cassiobury and Grove estates. Consequently, although the road and canal follow the easier valley route, the railway company was forced to build an expensive tunnel under Leavesden to the north of the town.

St Albans Road railway station (1837)

Watford's original railway station opened in 1837 on the west side of St Albans Road, a small, single-storey red-brick building. It closed in 1858 when it was replaced by a new, larger station at Watford Junction approximately 200 metres (220 yd) further south-east. The old station house still stands today; it is a Grade-II-listed building and is now occupied by a second-hand car dealership.[11][12] Watford Junction railway station is situated to the north of the town centre.[13]

These developments gave the town excellent communications and stimulated its industrial growth during the 19th and 20th centuries. The Grand Union Canal, allowed coal to be brought into the district and paved the way for industrial development. The Watford Gas and Coke Company was formed in 1834 and gas works built. The canal allowed paper-making mills to be sited at Croxley. The John Dickinson and Co. mill beside the canal manufactured the Croxley brand of fine quality paper. There had been brewing in Watford from the 17th century and, by the 19th century, two industrial scale brewers Benskins and Sedgwicks were located in the town.[14] The parish church of St Mary's was extensively restored in 1871.[15] The town expanded slightly during this time. In 1851 a new street off the High Street was opened, King Street, followed by Queens Road and Clarendon Road in the early 1860s. During this time, Watford had a population of around 6,500[10] The railways also continued to expand from Watford during this period; the Watford and Rickmansworth Railway opened in 1862 as a short branch line via Watford High Street to Rickmansworth (Church Street), and another branch was added to Croxley Green in 1912. The original plan was to extend the Rickmansworth line south connecting Watford to Uxbridge; this scheme failed and both the Rickmansworth and Croxley branches eventually closed.[16]

By 1891 the population of the town had risen to 17,063 and it had become very cramped. Local landowners sold land for the development of the town and it was bought up by commercial interests. Various factories and other works sprung up in Watford, mostly breweries and prints, but also engineering works, a steam laundry, a cold storage company and a cocoa processing plant. The town expanded rapidly, most of the new inhabitants moving in from London.[10]

At the start of the 20th century the town was growing fast. New roads were laid out in Callowland, North Watford, and in West Watford on farmland. Many continued to live in the cramped and unsanitary houses in the yards and alley-ways opening off the High Street.[17] Some of these people were among those who rioted in 1902 when the celebration for King Edward VII's coronation was postponed.[18] The Council had a programme of slum clearance which stopped with the outbreak of World War I in 1914. Building council houses resumed after the war and in the 1920s the Harebreaks estate was developed.

By the 1920s, printing had become the biggest industry in Watford. The biggest printers in the town were Sun Printers Ltd and Odhams Press. Watford was the biggest printing centre in the world and many advances in printing were made in Watford. During World War II the prints were taken over by the government who used them to print propaganda. After the war, the printing industry began going into decline. Union activity was common in Watford and advances in technology meant much of the industry became obsolete. Odhams Press closed down in 1978 and The Sun moved out of Watford during the 1980s after market reforms allowed it to do so.[19]

Watford is a major regional centre in the northern home counties. Hertfordshire County Council designates Watford and Stevenage to be its major sub-regional centres, heading its list of preferred sites for retail development.[33]
The High Street is the main focus of activity at night having a high concentration of the town's bars, clubs and restaurants. The primary shopping area is the Harlequin Shopping Centre, a large purpose-built indoor mall with over 140 shops, restaurants and cafes built during the 1990s, opened officially in June 1992. The owners of the shopping centre, Capital Shopping Centres, rebranded all their shopping centres, resulting in The Harlequin changing name to intu Watford Shopping Centre from May 2013.[34]

The town was home to the Scammell Lorries factory from 1922 until 1988. The site is now a residential area. Tandon Motorcycles, founded by Devdutt Tandon, were manufactured in Colne Way from 1947 until 1959.

The name Cassiobury has had various spellings over time. It is derived from 'Caegshoe', which is believed to be the combination of 'caeg', a person's name, and 'hoe', meaning a spur of land. When the land was granted to Sir Richard Morrison in the 16th century, it was called 'Cayshobury', with 'bury' indicating a manor.[4][8]

Cassiobury Park was formed from the grounds of Cassiobury House and consists of 190 acres (0.77 km2) of open space. The house was demolished in 1927 and the Cassiobury Gates in 1970, for road widening. In July 2007, the park won a Green Flag Award, which recognises the best green spaces in the country.[35] There is a children's play area, which includes a paddling pool, play equipment, a bouncy castle, an ice cream van, a kiosk where one may buy food, and 10.25" gauge miniature railway. The Grand Union Canal passes through the park.

Awarded Green Flag status since 2009, Cheslyn has been open to the public since 1965 as a formal gardens and house. The 3.5 acre gardens comprise a formal open area to the front and a semi-natural woodland area to the rear. Henry and Daisy Colbeck originally owned the house and gardens. Mr Colbeck was a renowned local architect, and designed Cheslyn House; he and his wife created the original gardens. The Colbecks travelled extensively, and this is reflected in the range of unusual and exotic plants in the gardens. Since the space has been open to the public it has been further developed, with new features added such as the pond, rock garden, large herbaceous borders and aviary.

Awarded Green Flag status since 2011, Woodside Playing Fields cover approximately 59 acres of playing fields, sports facilities and woodland. The site comprises a range of sports facilities including an eight lane synthetic track and stadium, an indoor bowls green, a community centre, cricket squares, football pitches and Woodside Leisure Centre. Woodside Stadium is home to Watford Harriers Athletics Club and hosts national level events such as the British Milers Club Grand Prix. The wider parkland includes two children's play areas and Albans Wood is a local nature reserve.

St Mary's is noted for its interior which was renovated in 1850 by the architect George Gilbert Scott and includes fine oak pews decorated in the Gothic Revival style. It also contains the Essex Chapel, which served at the burial place of the nobility of the Cassiobury Estate, including the Earls of Essex. The chapel contains a number of large, ornate marble tombs and memorials dating from the 16th century and later, and was described by Pevsner as "the chief glory of Watford Church".[36]

The Watford Palace Theatre is the only producing theatre in Hertfordshire. It presents world premières, dance, family shows and an annual traditional pantomime. Situated just off the High Street, the Edwardian building was opened in 1908 and the 600-seat theatre underwent a refurbishment in 2004. It houses its own rehearsal room, wardrobe, cafe, and bar. The Palace also shows films and 'live' and 'as live' streams of opera and ballet during its theatre season.

The Pump House Theatre and Arts Centre is based in an old pumping station situated just off the Lower High Street. The building was converted for use as a theatre, with rehearsal rooms, and meeting place for local arts based groups. Current facilities include a 124-seat theatre, rehearsal rooms, and live music venue. Community groups currently meeting at the Pump House include Dance House (children's ballet), Pump House Clog Morris (women's Morris dancing), Pump House Jazz (jazz club), Open House (live open mic music), Woodside Morris Men (men's Morris dancing), child, youth and adult theatre groups and also the Giggle Inn comedy club.[39] In 2018, the venue hosted the inaugural Watford Short Film Festival alongside Watford Museum.[40]

Watford Colosseum was built in 1938 as Watford Town Hall Assembly Rooms to the design of architect Charles Cowles-Voysey and acoustician Hope Bagenal.[41] It acquired a worldwide reputation for its fine acoustics,[42] and throughout the second half of the twentieth century it was used for concerts and recordings by leading orchestras and musicians.[43] Rising costs and falling attendance led the council to close it in 1994, reopening it in 1995 as the Colosseum in a joint management agreement with a commercial company who had previously operated at the Town and Country Club in London.[42][43] After the management company collapsed in 2004, the Colosseum was managed by Watford Council until April 2010, when it closed to undergo a £5.5 million refurbishment; reopening in August 2011 with new management.[44]

The acoustics were analysed by an acoustics company in 2009, who reported that the size and "shoebox" shape of Watford Colosseum; the flat floor and the materials used in construction; allow for pleasant reverberation and good sound quality and clarity, such as to make it among the best in Europe.[41]

Watford Museum, housed in a former brewery building on the Lower High Street, is home to a collection of fine art and sculpture which includes works by J. M. W. Turner, Sir Joshua Reynolds, William Blake and Jacob Epstein. The museum also hold special collections related to the Cassiobury Estate, Watford Football Club, and local heritage, as well as an archive collection of documents, printed ephemera, photographs and diaries related to Watford townsfolk, local government, nobility and businesses.[45]

The Hertfordshire Fire Museum is dedicated to the history of firefighting in the county. It is based in a purpose-built building at Watford Fire Station, on the same street as Watford Museum. The Museum includes a wide range of vehicles, equipment, uniforms and archive material.[46]

Warner Bros. Studios, Leavesden is an 80-hectare film studio complex which has been used for a wide range of Hollywood film productions. Part of the site is open to the public and houses the Making of Harry Potter Studio Tour, displaying costumes and sets from the Harry Potter films which were produced at Leavesden. The studio complex is to the north of the borough, around 2.5 miles (4.0 km) from the town centre, and a special shuttle bus provides a connection from Watford Junction station to the studios.

Watford is served by a number of different companies, including Arriva Shires & Essex, Arriva London, Uno, Red Rose Travel, Carousel, Mullany's Buses, Redline Buses and Tiger Line. Oyster Cards are accepted on TfL routes 142 (towards Brent Cross) and 258 (towards Harrow) into London. Intalink Explorer and Hertfordshire SaverCard is accepted on all but the London Bus routes.

Hourly bus services connect Watford Junction station and the town centre to London Heathrow Airport Airport on weekdays, with a service once every two hours at weekends and on bank holidays. Regular bus services run between Watford and Luton, but not directly to Luton Airport. Direct train services run from Watford Junction Station to Birmingham Airport.

Elstree Airfield is 3 miles (5 km) east of Watford. Several private charter companies and flying clubs are based there. Watford contains 2f flight squadron part of the air training core, 2f is the oldest running air cadet flights in the world.

A scheme to introduce light rail to Watford was conceived in 2009 when it was proposed that the Abbey Line should be converted to tram-train operation and run by Hertfordshire County Council.[50] The project was cancelled due to the complications and expense of transferring the line from National Rail to the county council.[51]

Watford is on the main Grand Union Canal route northwards from London. There is little commercial use, since the advent of the motorways, but the canal is used for recreational purposes. The River Gade and the River Colne flow through Watford.

Watford town centre and the surrounding area is relatively compact and the terrain is generally quite flat. Over 9 miles (14 km) of new cycle routes have been developed in the town since 2003 and a range of cycle maps are available locally. In Watford cycling to work makes up 2.2% of all journeys compared with 1.6% across the whole of Hertfordshire.[58]

National Cycle Routes 6 and 61 run across the eastern and southern sides of the town, utilising the off-road Ebury Way and Abbey Way. There is a continuous cycle route through the north-south axis of the town centre, including the pedestrianised parts along The Parade and High Street. Cycle parking is provided at intermittent points in the town centre and at local centres in the wider town.

The earliest records of schooling in Watford are of a schoolmaster named George Redhead in 1595, and of a Free School receiving an annual donation of £10 in 1640. The school consisted of "a room over two houses belonging to the Church Estate, nearest the churchyard."[5] In 1704, Elizabeth Fuller of Watford Place built a new Free School for forty boys and twenty girls on her land next to the churchyard, with rooms for a master and a mistress.[13] In the mid-19th century, the recorded schools in Watford were Fuller's Free School, by now in a poor state, and the separate boys and girls national schools of St Mary's in Church Street. All offered elementary education.

All the state-funded primary schools in Watford are co-educational. Under an earlier system, schools were divided into infant schools, covering Reception and Years 1 and 2, and junior schools, covering Years 3 to 6. Most such schools have amalgamated to form Junior Mixed Infant schools or (equivalently) primary schools, and all new schools are of this type. Within the municipal borough, there are now 6 linked pairs of infant schools and junior schools, and 14 JMI or primary schools, of which 2 are Roman Catholic.
Watford is also served by schools in the neighbouring districts of Three Rivers and Hertsmere.

Although all state-funded secondary schools in Hertfordshire are comprehensive, there is a great deal of differentiation in the southwestern corner of the county, centred on Watford but also including most of the Three Rivers district and Bushey in Hertsmere district.
Within this area, there are:[62]

Falconer School, a school for boys with emotional and behavioural difficulties.

The partially selective schools and Bushey Meads School operate common admissions tests in mathematics and non-verbal reasoning each autumn. In addition to those seeking selective places, all applicants to Bushey Meads and Queens' School, Bushey are required to take the tests, so they are taken by the majority of Year 6 children in the area. The partially selective schools also operate a common test and audition procedure to select children for specialist music places.[62]

Results achieved by the schools at GCSE are also widely spread, including the three highest and the two lowest scoring state schools within Hertfordshire.[65][66] The area also has by far the highest incidence in the county of children allocated to schools to which they had not applied.[67]

Watford is home to professional football team Watford F.C., who reached the 1984 FA Cup Final, also finishing as league Division One (now the Premier League) runners-up in 1983. They were relegated from Division One in 1988. In 1996, Watford was relegated from the new Division One (now the Football League Championship). Watford won the then Nationwide Division Two championship in 1998, then the following season (1998–99) reached the Premier League. The club was relegated the next season. After five years of uncertainty, Watford won the Football League Championship Play-Off Final achieving promotion to the Premier League in 2006, this time beating Leeds United A.F.C. by three goals to nil. The club was relegated to the Football League Championship after a single season (2006–2007) in the Premier League. They were promoted to the Premier League in 2015, after finishing 2nd in the Championship. Singer-songwriter Sir Elton John is a keen, long-term supporter of Watford F.C. and a former club chairman. He still maintains his links with Watford as Honorary Life President.[69] Between 1997 and 2013 the club shared its ground, Vicarage Road, with Saracens Rugby Football Club.

Watford has a Non-League football team Sun Sports F.C. who play at The Sun Postal Sports & Social Club. Watford were home to the Watford Cheetahs American Football team who played their home games at Fullerians R.F.C. between 2008 and 2012 and Glen Rovers, who play both Hurling and Gaelic Football. The town also has a cricket team, Watford Town, and several Sunday League football clubs.